Stephanie Giroux, a real estate agent in suburban Westwood, is nobody’s fool. She knows that education is like a giant nerve running along the spine of the middle-class Boston neighborhoods of Roslindale and West Roxbury. That’s why she targeted her recent sales efforts to coincide with the arrival of school assignment notices in Boston mailboxes.

“Every school is a great choice in Westwood,’’ reads Giroux’s postcard pitch to about 200 Boston families. So stop worrying about “school placements and entrance exams.’’

Giroux’s sales technique stirs up some queasiness in older Bostonians like me who recall the racist blockbusting tactics used by commission-hungry real estate agents during the 1960s and ’70s to push stable families out of Mattapan and Dorchester. Giroux is exploiting Boston’s vulnerabilities, too. But that’s where the comparison ends. There is nothing malevolent in her message. As a former West Roxbury resident, Giroux understands the stages of grief when a family does not receive a top choice in the city’s school assignment lottery: pain first; next numbness; then acute interest in suburban real estate.

Giroux’s bosses at Coldwell Banker are advising her to be sensitive in the use of future sales material. That’s good advice. But the real lesson here is for the growing field of mayoral candidates in Boston, one of whom will be directly accountable for the city’s public schools: Until middle-class parents in Boston can count on access to high quality schools in their own neighborhoods, many will follow the path to the suburbs.

Urban planners, meanwhile, gush over the renewal of America’s cities. They point gleefully to the so-called “bright flight’’ of highly educated young people who shed their suburban upbringings for the excitement of the city. Even their aging parents who no longer want to be saddled with big suburban homes are relocating to the city. Yet none of this can hide the gaping hole in even the most desirable urban areas.

Demographer Wendell Cox has analyzed where cohorts of 25- to 34-year-olds were living in 2000 and compared these findings to where they had settled down by 2010, upon reaching the ages 35 to 44. The illuminating results can be found on NewGeography.com: New York lost 15 percent of its cohort after a decade; San Francisco shed about 20 percent; and Boston lost nearly 40 percent of its cohort. It doesn’t say much for cities when maturation and happy additions to the family prompt calls for a moving van.

City Councilor and mayoral candidate John Connolly is way out in front of this issue. He is appealing directly to the 35-to-44-year-old set in Boston and pledging to embrace their issues, especially schools.

“You can’t build a city on young professionals and empty-nesters alone,’’ said Connolly. “You need rooted families.’’

Connolly is an outspoken critic of the city’s new assignment plan scheduled for implementation in the fall of 2014. The new plan is better than the current one that buses kids all over Kingdom Come. But Connolly said it still doesn’t provide enough predictability for parents. And it won’t stop the exodus of many middle-class parents if their children continue to be denied seats at desirable schools in their own neighborhoods.

Some brilliant people devised a complicated algorithm for the new Boston school assignment plan. And thoughtful people crafted a policy around it. But the suburban formula remains tough to beat: Buy a house in a nice neighborhood so the kids can go to a nice school. Smart cities, like Seattle, are adopting the suburban model. So should Boston.

Education is the only rational reason why a family in West Roxbury would want to uproot itself and move to Westwood, where houses are more expensive and property taxes are easily double. Both Westwood and West Roxbury are safe, middle-class communities with a nice system of parks and recreational opportunities. Each has commuter rail service to downtown. Teenagers in both communities complain that they have too little to do and gravitate to the Legacy Place mall in Dedham, which is about equidistant from both communities. Even the potential downside is similar: Youth sports in both places are hypercompetitive and can leave non-athletic kids feeling a little out of place.

Boston shouldn’t boast about its status as a truly livable city until it solves its school problem. Only then will the “Welcome to Westwood” sign lose its allure.